Printed circuit board for mounting at least one electronic part

Abstract

A printed circuit board is provided to which a device such as a tape carrier package having a multiplicity of leads arranged with a small pitch is connected by a local heating method using a bonding tool. The upper surfaces of solder layers provided on lands formed on the printed circuit board are flattened prior to leads of an electronic part to be mounted being placed on the solder layers. The leads are soldered to the lands by being pressed and heated with the bonding tool. At least a region of the printed circuit board corresponding to the bottom surface of the bonding tool has a height lower than that of the leads superposed on the lands, so that the desired parallelism of the bottom surface of the bonding tool with respect to the printed circuit board is maintained.

What is claimed is: 
     
       1. A printed circuit board comprising: a substrate on which at least one electronic part chip is mounted; and   positioning marks for positioning the at least one electronic part chip when the chip is mounted,   wherein said substrate has a multilayer structure having an inner layer formed by a blackening treatment over which said positioning marks are located.   
     
     
       2. A printed circuit board according to claim 1, wherein the lands, a conductive layer inside the printed circuit board, and the positioning marks are made of copper foil. 
     
     
       3. A printed circuit board according to claim 2, wherein the inner layer formed by a blackening treatment is a CuO film. 
     
     
       4. A printed circuit board according to claim 1, wherein the inner layer formed by a blackening treatment is provided in the conductive layer directly under the positioning marks. 
     
     
       5. A printed circuit board comprising: a plurality of lands for connection to leads of at least one electronic part, the lands being arranged in an array so that the lands point in a same direction, solder being mounted on a top surface of the lands;   a rectangular region on said printed circuit board in which said array of lands are located including outermost ones of the lands, said rectangular region including open regions extending from the outermost lands along longitudinal directions of the array of lands;   a resist formed outside of the rectangular region; and   a resin frame formed on the resist outside of and surrounding the rectangular region,   wherein only said array of the lands are located on an upper surface of the rectangular region of the printed circuit board, a height of the solder mounted on the top surface of the lands is a highest portion within the rectangular region and a top surface of the resin frame is higher than a top surface of the solder.   
     
     
       6. A printed circuit board according to claim 5, wherein said at least one electronic part has leads arranged along its four sides, and said rectangular region corresponds to said leads arranged along one of said four sides. 
     
     
       7. A printed circuit board according to claim 5, wherein the rectangular region is formed so that a bonding tool used for connection of the leads of the at least one electronic part to the lands can be positioned within the rectangular region. 
     
     
       8. A printed circuit board according to claim 7, wherein the pressing surface of the bonding tool has a rectangular shape, and the shape of the rectangular region on the printed circuit board is similar to the shape of the pressing surface of the bonding tool. 
     
     
       9. A printed circuit board comprising: a plurality of lands for connection to leads of at least one electronic part, the lands being arranged in an array so that the lands point in a same direction, solder being mounted on a top surface of the lands;   a rectangular region on the printed circuit board in which the array of said lands are located including outermost ones of the lands, said rectangular region including open regions extending from the outermost lands along longitudinal directions of the array of lands;   a resist formed outside of the rectangular region; and   a resin frame formed on the resist outside of and surrounding the rectangular region,   wherein only said array of lands are located on a surface of the rectangular region, and when the leads of the at least one electronic part are connected to the lands, a height of a top surface of the leads becomes a highest portion within the rectangular region and a top surface of the resin frame is at a higher position than the lands.   
     
     
       10. A printed circuit board according to claim 9, wherein the rectangular region is formed so that a bonding tool used for connection of the leads of the at least one electronic part to the lands can be positioned within the rectangular region. 
     
     
       11. A printed circuit board according to claim 10, wherein the pressing surface of the bonding tool has a rectangular shape, and the shape of the rectangular region on the printed circuit board is similar to the shape of the pressing surface of the bonding tool.